Thursday, March 22, 2012

722. Insecticides Are Tied to Honeybee Colony Collapse Disorder

New research has
linked springtime die-offs of honeybees critical for pollinating food crops --
part of the mysterious malady called colony collapse disorder -- with
technology for planting corn coated with insecticides.

The study,
published in ACS' journal Environmental Science & Technology, appears on
the eve of spring planting seasons in some parts of Europe where farmers use
the technology and widespread deaths of honeybees have occurred in the past.

In the study,
Andrea Tapparo and colleagues explain that seeds coated with so-called
neonicotinoid insecticides went into wide use in Europe in the late 1990s. The
insecticides are among the most widely used in the world, popular because they
kill insects by paralyzing nerves but have lower toxicity for other animals.
Almost immediately, beekeepers observed large die-offs of bees that seemed to
coincide with mid-March to May corn planting. Scientists thought this might be
due to particles of insecticide made airborne by the pneumatic drilling
machines used for planting. These machines forcefully suck seeds in and expel a
burst of air containing high concentrations of particles of the insecticide
coating. In an effort to make the pneumatic drilling method safer, the
scientists tested different types of insecticide coatings and seeding methods.

They found,
however, that all of the variations in seed coatings and planting methods
killed honeybees that flew through the emission cloud of the seeding machine.
One machine modified with a deflector to send the insecticide-laced air
downwards still caused the death of more than 200 bees foraging in the field.
The authors suggest that future work on this problem should focus on a way to
prevent the seeds from fragmenting inside the pneumatic drilling machines.

The
authors acknowledge funding from the University of Padova and the Ministero
delle Politiche Agricole Alimentari e Forestali, Italy.